<?php
namespace Smail\Mime;

use Smail\Mime\Message;

/**
 * mime.php
 *
 * This contains the functions necessary to detect and decode MIME
 * messages.
 *
 * @copyright 1999-2011 The SquirrelMail Project Team
 * @license http://opensource.org/licenses/gpl-license.php GNU Public License
 * @version $Id: mime.php 14121 2011-07-12 04:53:35Z pdontthink $
 * @package squirrelmail
 */

/**
 * The typical includes...
 */
// include('util/url_parser.php');
/* -------------------------------------------------------------------------- */
/* MIME DECODING */
/* -------------------------------------------------------------------------- */

/**
 * Get the MIME structure
 *
 * This function gets the structure of a message and stores it in the "message" class.
 * It will return this object for use with all relevant header information and
 * fully parsed into the standard "message" object format.
 */
function mime_structure($bodystructure, $flags = array())
{
    
    /* Isolate the body structure and remove beginning and end parenthesis. */
    $read = trim(substr($bodystructure, strpos(strtolower($bodystructure), 'bodystructure') + 13));
    $read = trim(substr($read, 0, - 1));
    $i = 0;
    $msg = Message::parseStructure($read, $i);
    if (! is_object($msg)) {
        exit();
    }
    if (count($flags)) {
        foreach ($flags as $flag) {
            $char = strtoupper($flag{1});
            switch ($char) {
                case 'S':
                    if (strtolower($flag) == '\\seen') {
                        $msg->is_seen = true;
                    }
                    break;
                case 'A':
                    if (strtolower($flag) == '\\answered') {
                        $msg->is_answered = true;
                    }
                    break;
                case 'D':
                    if (strtolower($flag) == '\\deleted') {
                        $msg->is_deleted = true;
                    }
                    break;
                case 'F':
                    if (strtolower($flag) == '\\flagged') {
                        $msg->is_flagged = true;
                    }
                    break;
                case 'M':
                    if (strtolower($flag) == '$mdnsent') {
                        $msg->is_mdnsent = true;
                    }
                    break;
                default:
                    break;
            }
        }
    }
    // listEntities($msg);
    return $msg;
}

/*
 * This starts the parsing of a particular structure. It is called recursively,
 * so it can be passed different structures. It returns an object of type
 * $message.
 * First, it checks to see if it is a multipart message. If it is, then it
 * handles that as it sees is necessary. If it is just a regular entity,
 * then it parses it and adds the necessary header information (by calling out
 * to mime_get_elements()
 */
function mime_fetch_body($imap_stream, $id, $ent_id = 1, $fetch_size = 0)
{
    $uid_support = true;
    /*
     * Do a bit of error correction. If we couldn't find the entity id, just guess
     * that it is the first one. That is usually the case anyway.
     */
    
    if (! $ent_id) {
        $cmd = "FETCH $id BODY[]";
    } else {
        $cmd = "FETCH $id BODY[$ent_id]";
    }
    
    if ($fetch_size != 0)
        $cmd .= "<0.$fetch_size>";
    $smail = new smail();
    $data = $smail->smimap_run_command($imap_stream, $cmd, true, $response, $message, $uid_support);
    do {
        $topline = trim(array_shift($data));
    } while ($topline && ($topline[0] == '*') && ! preg_match('/\* [0-9]+ FETCH.*/i', $topline));
    
    $wholemessage = implode('', $data);
    if (preg_match('/\{([^\}]*)\}/', $topline, $regs)) {
        $ret = substr($wholemessage, 0, $regs[1]);
        /*
         * There is some information in the content info header that could be important
         * in order to parse html messages. Let's get them here.
         */
        // if ($ret{0} == '<') {
        // $data = sqimap_run_command ($imap_stream, "FETCH $id BODY[$ent_id.MIME]", true, $response, $message, $uid_support);
        // }
    } else 
        if (preg_match('/"([^"]*)"/', $topline, $regs)) {
            $ret = $regs[1];
        } else 
            if ((stristr($topline, 'nil') !== false) && (empty($wholemessage))) {
                $ret = $wholemessage;
            } else {
                global $where, $what, $mailbox, $passed_id, $startMessage;
                $par = 'mailbox=' . urlencode($mailbox) . '&amp;passed_id=' . $passed_id;
                if (isset($where) && isset($what)) {
                    $par .= '&amp;where=' . urlencode($where) . '&amp;what=' . urlencode($what);
                } else {
                    $par .= '&amp;startMessage=' . $startMessage . '&amp;show_more=0';
                }
                $par .= '&amp;response=' . urlencode($response) . '&amp;message=' . urlencode($message) . '&amp;topline=' . urlencode($topline);
                
                echo '<tt><br />' . '<table width="80%"><tr>' . '<tr><td colspan="2">' . "Body retrieval error. The reason for this is most probably that the message is malformed." . '</td></tr>' . '<tr><td><b>' . _("Command:") . "</td><td>$cmd</td></tr>" . '<tr><td><b>' . _("Response:") . "</td><td>$response</td></tr>" . '<tr><td><b>' . _("Message:") . "</td><td>$message</td></tr>" . '<tr><td><b>' . _("FETCH line:") . "</td><td>$topline</td></tr>" . "</table><br /></tt></font><hr />";
                
                $data = $smail->smimap_run_command($imap_stream, "FETCH $passed_id BODY[]", true, $response, $message, $uid_support);
                array_shift($data);
                $wholemessage = implode('', $data);
                $ret = $wholemessage;
            }
    return $ret;
}

function mime_print_body_lines($imap_stream, $id, $ent_id = 1, $encoding, $rStream = 'php://stdout')
{
    global $uid_support;
    
    /*
     * Don't kill the connection if the browser is over a dialup
     * and it would take over 30 seconds to download it.
     * Don't call set_time_limit in safe mode.
     */
    
    if (! ini_get('safe_mode')) {
        set_time_limit(0);
    }
    /*
     * in case of base64 encoded attachments, do not buffer them.
     * Instead, echo the decoded attachment directly to screen
     */
    if (strtolower($encoding) == 'base64') {
        if (! $ent_id) {
            $query = "FETCH $id BODY[]";
        } else {
            $query = "FETCH $id BODY[$ent_id]";
        }
        $smail = new smail();
        $smail->smimap_run_command($imap_stream, $query, true, $response, $message, $uid_support, 'sqimap_base64_decode', $rStream, true);
    } else {
        $body = mime_fetch_body($imap_stream, $id, $ent_id);
        if ($rStream !== 'php://stdout') {
            fwrite($rStream, decodeBody($body, $encoding));
        } else {
            echo decodeBody($body, $encoding);
        }
    }
    return;
}

/* -[ END MIME DECODING ]----------------------------------------------------------- */

/*
 * This is here for debugging purposes. It will print out a list
 * of all the entity IDs that are in the $message object.
 */
function listEntities($message)
{
    if ($message) {
        echo "<tt>" . $message->entity_id . ' : ' . $message->type0 . '/' . $message->type1 . ' parent = ' . $message->parent->entity_id . '<br />';
        for ($i = 0; isset($message->entities[$i]); $i ++) {
            echo "$i : ";
            $msg = listEntities($message->entities[$i]);
            
            if ($msg) {
                echo "return: ";
                return $msg;
            }
        }
    }
}

/**
 * 显示邮件优先级
 *
 * @param
 *            $priority
 */
function getPriorityStr($priority)
{
    $priority_level = substr($priority, 0, 1);
    
    switch ($priority_level) {
        /* Check for a higher then normal priority. */
        case '1':
        case '2':
            $priority_string = '高';
            break;
        /* Check for a lower then normal priority. */
        case '4':
        case '5':
            $priority_string = '低';
            break;
        /* Check for a normal priority. */
        case '3':
        default:
            $priority_level = '3';
            $priority_string = '正常';
            break;
    }
    return $priority_string;
}

/* returns a $message object for a particular entity id */
function getEntity($message, $ent_id)
{
    return $message->getEntity($ent_id);
}

/*
 * translateText
 * Extracted from strings.php 23/03/2002
 */
function translateText(&$body, $wrap_at, $charset)
{
    global $where, $what; /* from searching */
    global $color; /* color theme */
    
    require_once (SM_PATH . 'action/url_parser.php');
    
    $body_ary = explode("\n", $body);
    for ($i = 0; $i < count($body_ary); $i ++) {
        $line = $body_ary[$i];
        if (strlen($line) - 2 >= $wrap_at) {
            sqWordWrap($line, $wrap_at, $charset);
        }
        $charset = strtolower($charset);
        if ($charset == 'gbk' || $charset == 'gb2312' || $charset == 'gb18030') {
            $line = iconv($charset, 'utf-8//IGNORE', $line);
        }
        // $line = charset_decode($charset, $line);
        $line = str_replace("\t", '        ', $line);
        parseUrl($line);
        $quotes = 0;
        $pos = 0;
        $j = strlen($line);
        
        while ($pos < $j) {
            if ($line[$pos] == ' ') {
                $pos ++;
            } else 
                if (strpos($line, '&gt;', $pos) === $pos) {
                    $pos += 4;
                    $quotes ++;
                } else {
                    break;
                }
        }
        if ($quotes % 2) {
            if (! isset($color[13])) {
                $color[13] = '#800000';
            }
            $line = '<font color="' . $color[13] . '">' . $line . '</font>';
        } elseif ($quotes) {
            if (! isset($color[14])) {
                $color[14] = '#FF0000';
            }
            $line = '<font color="' . $color[14] . '">' . $line . '</font>';
        }
        $body_ary[$i] = $line;
    }
    $body = '<pre>' . implode("\n", $body_ary) . '</pre>';
}

/**
 * This returns a parsed string called $body.
 * That string can then
 * be displayed as the actual message in the HTML. It contains
 * everything needed, including HTML Tags, Attachments at the
 * bottom, etc.
 */
function formatBody($imap_stream, $message, $color, $wrap_at, $ent_num, $id, $mailbox = 'INBOX')
{
    global $startMessage, $has_unsafe_images;
    
    $body = '';
    $body_message = getEntity($message, $ent_num);
    if (($body_message->header->type0 == 'text') || ($body_message->header->type0 == 'rfc822')) {
        $body = mime_fetch_body($imap_stream, $id, $ent_num);
        $body = decodeBody($body, $body_message->header->encoding);
        /*
         * If there are other types that shouldn't be formatted, add
         * them here.
         */
        $show_html_default = 1;
        if ($body_message->header->type1 == 'html') {
            if ($show_html_default != 1) {
                $entity_conv = array(
                    '&nbsp;' => ' ',
                    '<p>' => "\n",
                    '<P>' => "\n",
                    '<br>' => "\n",
                    '<BR>' => "\n",
                    '<br />' => "\n",
                    '<BR />' => "\n",
                    '&gt;' => '>',
                    '&lt;' => '<'
                );
                $body = strtr($body, $entity_conv);
                $body = strip_tags($body);
                $body = trim($body);
                translateText($body, $wrap_at, $body_message->header->getParameter('charset'));
            } else {
                $charset = $body_message->header->getParameter('charset');
                if (! empty($charset)) {
                    $charset = strtolower($charset);
                    if ($charset == 'gbk' || $charset == 'gb2312' || $charset == 'gb18030') {
                        $body = iconv($charset, 'utf-8//IGNORE', $body);
                    }
                    $body = magicHTML($body, $id, $message, $mailbox);
                }
            }
        } else {
            $charset = $body_message->header->getParameter('charset');
            translateText($body, $wrap_at, $charset);
        }
    }
    return $body;
}

/**
 * 附件
 *
 * @param
 *            $message
 * @param
 *            $exclude_id
 * @param
 *            $mailbox
 * @param
 *            $id
 */
function formatAttachments($message, $exclude_id, $mailbox, $id)
{
    $att_ar = $message->getAttachments($exclude_id);
    if (! count($att_ar))
        return '';
    $urlMailbox = urlencode($mailbox);
    $i = 0;
    foreach ($att_ar as $att) {
        $ent = $att->entity_id;
        $header = $att->header;
        $type0 = strtolower($header->type0);
        $type1 = strtolower($header->type1);
        $name = '';
        // $links['download link']['text'] = 'Download';
        // $links['download link']['href'] = SM_PATH .
        // "src/download.php?absolute_dl=true&amp;passed_id=$id&amp;mailbox=$urlMailbox&amp;ent_id=$ent";
        // $ImageURL = '';
        if ($type0 == 'message' && $type1 == 'rfc822') {
            // $default_page = SM_PATH . 'src/read_body.php';
            $rfc822_header = $att->rfc822_header;
            $filename = $rfc822_header->subject;
            if (trim($filename) == '') {
                $filename = 'untitled-[' . $ent . ']';
            }
            $from_o = $rfc822_header->from;
            if (is_object($from_o)) {
                $from_name = $from_o->getAddress(false);
            } elseif (is_array($from_o) && count($from_o) && is_object($from_o[0])) {
                $from_name = $from_o[0]->getAddress(false);
            } else {
                $from_name = _("Unknown sender");
            }
            $from_name = decodeHeader(($from_name));
            $description = $from_name;
        } else {
            // $default_page = SM_PATH . 'src/download.php';
            if (is_object($header->disposition)) {
                $filename = $header->disposition->getProperty('filename');
                if (trim($filename) == '') {
                    $name = decodeHeader($header->disposition->getProperty('name'));
                    if (trim($name) == '') {
                        $name = $header->getParameter('name');
                        if (trim($name) == '') {
                            if (trim($header->id) == '') {
                                $filename = 'untitled-[' . $ent . ']' . '.' . strtolower($header->type1);
                            } else {
                                $filename = 'cid: ' . $header->id . '.' . strtolower($header->type1);
                            }
                        } else {
                            $filename = $name;
                        }
                    } else {
                        $filename = $name;
                    }
                }
            } else {
                $filename = $header->getParameter('name');
                if (! trim($filename)) {
                    if (trim($header->id) == '') {
                        return;
                        $filename = 'untitled-[' . $ent . ']' . '.' . strtolower($header->type1);
                    } else {
                        $filename = 'cid: ' . $header->id . '.' . strtolower($header->type1);
                    }
                }
            }
            if ($header->description) {
                $description = decodeHeader($header->description);
            } else {
                $description = '';
            }
        }
        
        // $display_filename = $filename;
        // if (isset($passed_ent_id)) {
        // $passed_ent_id_link = '&amp;passed_ent_id='.$passed_ent_id;
        // } else {
        // $passed_ent_id_link = '';
        // }
        // $defaultlink = $default_page . "?startMessage=$startMessage"
        // . "&amp;passed_id=$id&amp;mailbox=$urlMailbox"
        // . '&amp;ent_id='.$ent.$passed_ent_id_link;
        // if ($where && $what) {
        // $defaultlink .= '&amp;where='. urlencode($where).'&amp;what='.urlencode($what);
        // }
        // // IE does make use of mime content sniffing. Forcing a download
        // // prohibit execution of XSS inside an application/octet-stream attachment
        // if ($type0 == 'application' && $type1 == 'octet-stream') {
        // $defaultlink .= '&amp;absolute_dl=true';
        // }
        
        // $attachments .= '<tr><td>' .
        // '<a href="'.$defaultlink.'">'.decodeHeader($display_filename).'</a></td>' .
        // '<td><small><b>' . show_readable_size($header->size) .
        // '</b></small></td>' .
        // '<td><small>[ '.htmlspecialchars($type0).'/'.htmlspecialchars($type1).' ]</small></td>' .
        // '<td><small>';
        // $attachments .= '<b>' . $description . '</b>';
        //
        // $skipspaces = 1;
        // foreach ($links as $val) {
        // if ($skipspaces) {
        // $skipspaces = 0;
        // } else {
        // $attachments .= '&nbsp;&nbsp;|&nbsp;&nbsp;';
        // }
        // $attachments .= '<a href="' . $val['href'] . '">' . $val['text'] . '</a>';
        // }
        // unset($links);
        // $attachments .= "</td></tr>";
        $attachments[$i]['filename'] = decodeHeader($filename);
        $attachments[$i]['type'] = htmlspecialchars($type0) . '/' . htmlspecialchars($type1);
        $attachments[$i]['description'] = $description;
        $attachments[$i]['size'] = show_readable_size($header->size);
        $i ++;
    }
    return $attachments;
}

function sqimap_base64_decode(&$string)
{
    
    // Base64 encoded data goes in pairs of 4 bytes. To achieve on the
    // fly decoding (to reduce memory usage) you have to check if the
    // data has incomplete pairs
    
    // Remove the noise in order to check if the 4 bytes pairs are complete
    $string = str_replace(array(
        "\r\n",
        "\n",
        "\r",
        " "
    ), array(
        '',
        '',
        '',
        ''
    ), $string);
    
    $sStringRem = '';
    $iMod = strlen($string) % 4;
    if ($iMod) {
        $sStringRem = substr($string, - $iMod);
        // Check if $sStringRem contains padding characters
        if (substr($sStringRem, - 1) != '=') {
            $string = substr($string, 0, - $iMod);
        } else {
            $sStringRem = '';
        }
    }
    $string = base64_decode($string);
    return $sStringRem;
}

/**
 * Decodes encoded message body
 *
 * This function decodes the body depending on the encoding type.
 * Currently quoted-printable and base64 encodings are supported.
 * decode_body hook was added to this function in 1.4.2/1.5.0
 * 
 * @param string $body
 *            encoded message body
 * @param string $encoding
 *            used encoding
 * @return string decoded string
 * @since 1.0
 */
function decodeBody($body, $encoding)
{
    $body = str_replace("\r\n", "\n", $body);
    $encoding = strtolower($encoding);
    
    // $encoding_handler = do_hook_function('decode_body', $encoding);
    
    // plugins get first shot at decoding the body
    if (! empty($encoding_handler) && function_exists($encoding_handler)) {
        $body = $encoding_handler('decode', $body);
    } elseif ($encoding == 'quoted-printable' || $encoding == 'quoted_printable') {
        /**
         * quoted_printable_decode() function is broken in older
         * php versions.
         * Text with \r\n decoding was fixed only
         * in php 4.3.0. Minimal code requirement 4.0.4 +
         * str_replace("\r\n", "\n", $body); call.
         */
        $body = quoted_printable_decode($body);
    } elseif ($encoding == 'base64') {
        $body = base64_decode($body);
    }
    
    return $body;
}

/**
 * Decodes headers
 *
 * This functions decode strings that is encoded according to
 * RFC1522 (MIME Part Two: Message Header Extensions for Non-ASCII Text).
 * Patched by Christian Schmidt <christian@ostenfeld.dk> 23/03/2002
 */
function decodeHeader($string, $utfencode = true, $htmlsave = true, $decide = false)
{
    $default_charset;
    if (is_array($string)) {
        $string = implode("\n", $string);
    }
    
    $i = 0;
    $iLastMatch = - 2;
    $encoded = false;
    
    $aString = explode(' ', $string);
    $ret = '';
    foreach ($aString as $chunk) {
        if ($encoded && $chunk === '') {
            continue;
        } elseif ($chunk === '') {
            $ret .= ' ';
            continue;
        }
        $encoded = false;
        /* if encoded words are not separated by a linear-space-white we still catch them */
        $j = $i - 1;
        
        while ($match = preg_match('/^(.*)=\?([^?]*)\?(Q|B)\?([^?]*)\?=(.*)$/Ui', $chunk, $res)) {
            /* if the last chunk isn't an encoded string then put back the space, otherwise don't */
            if ($iLastMatch !== $j) {
                if ($htmlsave) {
                    $ret .= '&#32;';
                } else {
                    $ret .= ' ';
                }
            }
            $iLastMatch = $i;
            $j = $i;
            if ($htmlsave) {
                $ret .= htmlspecialchars($res[1]);
            } else {
                $ret .= $res[1];
            }
            $encoding = ucfirst($res[3]);
            $code = $res[2];
            /* decide about valid decoding */
            if ($decide) {
                $can_be_encoded = true;
            } else {
                $can_be_encoded = false;
            }
            
            switch ($encoding) {
                case 'B':
                    $replace = base64_decode($res[4]);
                    if ($can_be_encoded) {
                        // string is converted from one charset to another. sanitizing depends on $htmlsave
                        $replace = charset_convert($res[2], $replace, $default_charset, $htmlsave);
                    } elseif ($utfencode) {
                        // string is converted to htmlentities and sanitized
                        // $replace = charset_decode($res[2],$replace);
                        $replace = iconv($code, 'utf-8', $replace);
                    } elseif ($htmlsave) {
                        // string is not converted, but still sanitized
                        $replace = htmlspecialchars($replace);
                    }
                    $ret .= $replace;
                    break;
                case 'Q':
                    $replace = str_replace('_', ' ', $res[4]);
                    $replace = preg_replace('/=([0-9a-f]{2})/ie', 'chr(hexdec("\1"))', $replace);
                    if ($can_be_encoded) {
                        // string is converted from one charset to another. sanitizing depends on $htmlsave
                        $replace = charset_convert($res[2], $replace, $default_charset, $htmlsave);
                    } elseif ($utfencode) {
                        // string is converted to html entities and sanitized
                        // $replace = charset_decode($res[2], $replace);
                        $replace = iconv($zh_cn, 'utf-8', $replace);
                    } elseif ($htmlsave) {
                        // string is not converted, but still sanizited
                        $replace = htmlspecialchars($replace);
                    }
                    $ret .= $replace;
                    break;
                default:
                    break;
            }
            $chunk = $res[5];
            $encoded = true;
        }
        if (! $encoded) {
            if ($htmlsave) {
                $ret .= '&#32;';
            } else {
                $ret .= ' ';
            }
        }
        
        if (! $encoded && $htmlsave) {
            $ret .= htmlspecialchars($chunk);
        } else {
            $ret .= $chunk;
        }
        ++ $i;
    }
    /* remove the first added space */
    if ($ret) {
        if ($htmlsave) {
            $ret = substr($ret, 5);
        } else {
            $ret = substr($ret, 1);
        }
    }
    return $ret;
}

/**
 * Encodes header as quoted-printable
 *
 * Encode a string according to RFC 1522 for use in headers if it
 * contains 8-bit characters or anything that looks like it should
 * be encoded.
 */
function encodeHeader($string, $default_charset = 'utf-8')
{
    // Use B encoding for multibyte charsets
    $mb_charsets = array(
        'utf-8',
        'big5',
        'gb2312',
        'euc-kr',
        'gbk'
    );
    if (in_array($default_charset, $mb_charsets)) {
        return encodeHeaderBase64($string, $default_charset);
    }
    
    // Encode only if the string contains 8-bit characters or =?
    $j = strlen($string);
    $max_l = 75 - strlen($default_charset) - 7;
    $aRet = array();
    $ret = '';
    $iEncStart = $enc_init = false;
    $cur_l = $iOffset = 0;
    for ($i = 0; $i < $j; ++ $i) {
        switch ($string{$i}) {
            case '"':
            case '=':
            case '<':
            case '>':
            case ',':
            case '?':
            case '_':
                if ($iEncStart === false) {
                    $iEncStart = $i;
                }
                $cur_l += 3;
                if ($cur_l > ($max_l - 2)) {
                    /* if there is an stringpart that doesn't need encoding, add it */
                    $aRet[] = substr($string, $iOffset, $iEncStart - $iOffset);
                    $aRet[] = "=?$default_charset?Q?$ret?=";
                    $iOffset = $i;
                    $cur_l = 0;
                    $ret = '';
                    $iEncStart = false;
                } else {
                    $ret .= sprintf("=%02X", ord($string{$i}));
                }
                break;
            case '(':
            case ')':
                if ($iEncStart !== false) {
                    $aRet[] = substr($string, $iOffset, $iEncStart - $iOffset);
                    $aRet[] = "=?$default_charset?Q?$ret?=";
                    $iOffset = $i;
                    $cur_l = 0;
                    $ret = '';
                    $iEncStart = false;
                }
                break;
            case ' ':
                if ($iEncStart !== false) {
                    $cur_l ++;
                    if ($cur_l > $max_l) {
                        $aRet[] = substr($string, $iOffset, $iEncStart - $iOffset);
                        $aRet[] = "=?$default_charset?Q?$ret?=";
                        $iOffset = $i;
                        $cur_l = 0;
                        $ret = '';
                        $iEncStart = false;
                    } else {
                        $ret .= '_';
                    }
                }
                break;
            default:
                $k = ord($string{$i});
                if ($k > 126) {
                    if ($iEncStart === false) {
                        // do not start encoding in the middle of a string, also take the rest of the word.
                        $sLeadString = substr($string, 0, $i);
                        $aLeadString = explode(' ', $sLeadString);
                        $sToBeEncoded = array_pop($aLeadString);
                        $iEncStart = $i - strlen($sToBeEncoded);
                        $ret .= $sToBeEncoded;
                        $cur_l += strlen($sToBeEncoded);
                    }
                    $cur_l += 3;
                    /* first we add the encoded string that reached it's max size */
                    if ($cur_l > ($max_l - 2)) {
                        $aRet[] = substr($string, $iOffset, $iEncStart - $iOffset);
                        $aRet[] = "=?$default_charset?Q?$ret?= "; /* the next part is also encoded => separate by space */
                        $cur_l = 3;
                        $ret = '';
                        $iOffset = $i;
                        $iEncStart = $i;
                    }
                    $enc_init = true;
                    $ret .= sprintf("=%02X", $k);
                } else {
                    if ($iEncStart !== false) {
                        $cur_l ++;
                        if ($cur_l > $max_l) {
                            $aRet[] = substr($string, $iOffset, $iEncStart - $iOffset);
                            $aRet[] = "=?$default_charset?Q?$ret?=";
                            $iEncStart = false;
                            $iOffset = $i;
                            $cur_l = 0;
                            $ret = '';
                        } else {
                            $ret .= $string{$i};
                        }
                    }
                }
                break;
        }
    }
    
    if ($enc_init) {
        if ($iEncStart !== false) {
            $aRet[] = substr($string, $iOffset, $iEncStart - $iOffset);
            $aRet[] = "=?$default_charset?Q?$ret?=";
        } else {
            $aRet[] = substr($string, $iOffset);
        }
        $string = implode('', $aRet);
    }
    return $string;
}

/**
 * Encodes string according to rfc2047 B encoding header formating rules
 *
 * It is recommended way to encode headers with character sets that store
 * symbols in more than one byte.
 *
 * Function requires mbstring support. If required mbstring functions are missing,
 * function returns false and sets E_USER_WARNING level error message.
 *
 * Minimal requirements - php 4.0.6 with mbstring extension. Please note,
 * that mbstring functions will generate E_WARNING errors, if unsupported
 * character set is used. mb_encode_mimeheader function provided by php
 * mbstring extension is not used in order to get better control of header
 * encoding.
 *
 * Used php code functions - function_exists(), trigger_error(), strlen()
 * (is used with charset names and base64 strings). Used php mbstring
 * functions - mb_strlen and mb_substr.
 *
 * Related documents: rfc 2045 (BASE64 encoding), rfc 2047 (mime header
 * encoding), rfc 2822 (header folding)
 *
 * @param string $string
 *            header string that must be encoded
 * @param string $charset
 *            character set. Must be supported by mbstring extension.
 *            Use sq_mb_list_encodings() to detect supported charsets.
 * @return string string encoded according to rfc2047 B encoding formating rules
 * @since 1.5.1 and 1.4.6
 */
function encodeHeaderBase64($string, $charset)
{
    /**
     * Check mbstring function requirements.
     */
    if (! function_exists('mb_strlen') || ! function_exists('mb_substr')) {
        // set E_USER_WARNING
        trigger_error('encodeHeaderBase64: Required mbstring functions are missing.', E_USER_WARNING);
        // return false
        return false;
    }
    
    // initial return array
    $aRet = array();
    
    /**
     * header length = 75 symbols max (same as in encodeHeader)
     * remove $charset length
     * remove =? ? ?= (5 chars)
     * remove 2 more chars (\r\n ?)
     */
    $iMaxLength = 75 - strlen($charset) - 7;
    
    // set first character position
    $iStartCharNum = 0;
    
    // loop through all characters. count characters and not bytes.
    for ($iCharNum = 1; $iCharNum <= mb_strlen($string, $charset); $iCharNum ++) {
        // encode string from starting character to current character.
        $encoded_string = base64_encode(mb_substr($string, $iStartCharNum, $iCharNum - $iStartCharNum, $charset));
        
        // Check encoded string length
        if (strlen($encoded_string) > $iMaxLength) {
            // if string exceeds max length, reduce number of encoded characters and add encoded string part to array
            $aRet[] = base64_encode(mb_substr($string, $iStartCharNum, $iCharNum - $iStartCharNum - 1, $charset));
            
            // set new starting character
            $iStartCharNum = $iCharNum - 1;
            
            // encode last char (in case it is last character in string)
            $encoded_string = base64_encode(mb_substr($string, $iStartCharNum, $iCharNum - $iStartCharNum, $charset));
        } // if string is shorter than max length - add next character
    }
    
    // add last encoded string to array
    $aRet[] = $encoded_string;
    
    // set initial return string
    $sRet = '';
    
    // loop through encoded strings
    foreach ($aRet as $string) {
        // TODO: Do we want to control EOL (end-of-line) marker
        if ($sRet != '')
            $sRet .= " ";
            
            // add header tags and encoded string to return string
        $sRet .= '=?' . $charset . '?B?' . $string . '?=';
    }
    
    return $sRet;
}

/* This function trys to locate the entity_id of a specific mime element */
function find_ent_id($id, $message)
{
    for ($i = 0, $ret = ''; $ret == '' && $i < count($message->entities); $i ++) {
        if ($message->entities[$i]->header->type0 == 'multipart') {
            $ret = find_ent_id($id, $message->entities[$i]);
        } else {
            if (strcasecmp($message->entities[$i]->header->id, $id) == 0) {
                // if (sq_check_save_extension($message->entities[$i])) {
                return $message->entities[$i]->entity_id;
                // }
            } elseif (! empty($message->entities[$i]->header->parameters['name'])) {
                /**
                 * This is part of a fix for Outlook Express 6.x generating
                 * cid URLs without creating content-id headers
                 * @@JA - 20050207
                 */
                if (strcasecmp($message->entities[$i]->header->parameters['name'], $id) == 0) {
                    return $message->entities[$i]->entity_id;
                }
            }
        }
    }
    return $ret;
}

/**
 * the picture attachment save type for example gif\png
 *
 * @param
 *            $message
 */
function sq_check_save_extension($message)
{
    $filename = $message->getFilename();
    $ext = substr($filename, strrpos($filename, '.') + 1);
    $save_extensions = array(
        'jpg',
        'jpeg',
        'gif',
        'png',
        'bmp'
    );
    return in_array($ext, $save_extensions);
}

/**
 * * HTMLFILTER ROUTINES
 */

/**
 * This function checks attribute values for entity-encoded values
 * and returns them translated into 8-bit strings so we can run
 * checks on them.
 *
 * @param $attvalue A
 *            string to run entity check against.
 * @return Nothing, modifies a reference value.
 */
function sq_defang(&$attvalue)
{
    $me = 'sq_defang';
    /**
     * Skip this if there aren't ampersands or backslashes.
     */
    if (strpos($attvalue, '&') === false && strpos($attvalue, '\\') === false) {
        return;
    }
    $m = false;
    do {
        $m = false;
        $m = $m || sq_deent($attvalue, '/\&#0*(\d+);*/s');
        $m = $m || sq_deent($attvalue, '/\&#x0*((\d|[a-f])+);*/si', true);
        $m = $m || sq_deent($attvalue, '/\\\\(\d+)/s', true);
    } while ($m == true);
    $attvalue = stripslashes($attvalue);
}

/**
 * Kill any tabs, newlines, or carriage returns.
 * Our friends the
 * makers of the browser with 95% market value decided that it'd
 * be funny to make "java[tab]script" be just as good as "javascript".
 *
 * @param
 *            attvalue The attribute value before extraneous spaces removed.
 * @return attvalue Nothing, modifies a reference value.
 */
function sq_unspace(&$attvalue)
{
    $me = 'sq_unspace';
    if (strcspn($attvalue, "\t\r\n\0 ") != strlen($attvalue)) {
        $attvalue = str_replace(Array(
            "\t",
            "\r",
            "\n",
            "\0",
            " "
        ), Array(
            '',
            '',
            '',
            '',
            ''
        ), $attvalue);
    }
}

/**
 * Translate all dangerous Unicode or Shift_JIS characters which are accepted by
 * IE as regular characters.
 *
 * @param
 *            attvalue The attribute value before dangerous characters are translated.
 * @return attvalue Nothing, modifies a reference value.
 * @author Marc Groot Koerkamp.
 */
function sq_fixIE_idiocy(&$attvalue)
{
    // remove NUL
    $attvalue = str_replace("\0", "", $attvalue);
    // remove comments
    $attvalue = preg_replace("/(\/\*.*?\*\/)/", "", $attvalue);
    
    // IE has the evil habit of accepting every possible value for the attribute expression.
    // The table below contains characters which are parsed by IE if they are used in the "expression"
    // attribute value.
    $aDangerousCharsReplacementTable = array(
        array(
            '&#x029F;',
            '&#0671;' ,/* L UNICODE IPA Extension */
                              '&#x0280;',
            '&#0640;' ,/* R UNICODE IPA Extension */
                              '&#x0274;',
            '&#0628;' ,/* N UNICODE IPA Extension */
                              '&#xFF25;',
            '&#65317;' ,/* Unicode FULLWIDTH LATIN CAPITAL LETTER E */
                              '&#xFF45;',
            '&#65349;' ,/* Unicode FULLWIDTH LATIN SMALL LETTER E */
                              '&#xFF38;',
            '&#65336;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER X */
                              '&#xFF58;',
            '&#65368;',/* Unicode FULLWIDTH LATIN SMALL LETTER X */
                              '&#xFF30;',
            '&#65328;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER P */
                              '&#xFF50;',
            '&#65360;',/* Unicode FULLWIDTH LATIN SMALL LETTER P */
                              '&#xFF32;',
            '&#65330;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER R */
                              '&#xFF52;',
            '&#65362;',/* Unicode FULLWIDTH LATIN SMALL LETTER R */
                              '&#xFF33;',
            '&#65331;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER S */
                              '&#xFF53;',
            '&#65363;',/* Unicode FULLWIDTH LATIN SMALL LETTER S */
                              '&#xFF29;',
            '&#65321;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER I */
                              '&#xFF49;',
            '&#65353;',/* Unicode FULLWIDTH LATIN SMALL LETTER I */
                              '&#xFF2F;',
            '&#65327;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER O */
                              '&#xFF4F;',
            '&#65359;',/* Unicode FULLWIDTH LATIN SMALL LETTER O */
                              '&#xFF2E;',
            '&#65326;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER N */
                              '&#xFF4E;',
            '&#65358;',/* Unicode FULLWIDTH LATIN SMALL LETTER N */
                              '&#xFF2C;',
            '&#65324;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER L */
                              '&#xFF4C;',
            '&#65356;',/* Unicode FULLWIDTH LATIN SMALL LETTER L */
                              '&#xFF35;',
            '&#65333;',/* Unicode FULLWIDTH LATIN CAPITAL LETTER U */
                              '&#xFF55;',
            '&#65365;',/* Unicode FULLWIDTH LATIN SMALL LETTER U */
                              '&#x207F;',
            '&#8319;' ,/* Unicode SUPERSCRIPT LATIN SMALL LETTER N */
                              "\xEF\xBC\xA5", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER E */   // in unicode this is some Chinese char range
                              "\xEF\xBD\x85", /* Shift JIS FULLWIDTH LATIN SMALL LETTER E */
                              "\xEF\xBC\xB8", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER X */
                              "\xEF\xBD\x98", /* Shift JIS FULLWIDTH LATIN SMALL LETTER X */
                              "\xEF\xBC\xB0", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER P */
                              "\xEF\xBD\x90", /* Shift JIS FULLWIDTH LATIN SMALL LETTER P */
                              "\xEF\xBC\xB2", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER R */
                              "\xEF\xBD\x92", /* Shift JIS FULLWIDTH LATIN SMALL LETTER R */
                              "\xEF\xBC\xB3", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER S */
                              "\xEF\xBD\x93", /* Shift JIS FULLWIDTH LATIN SMALL LETTER S */
                              "\xEF\xBC\xA9", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER I */
                              "\xEF\xBD\x89", /* Shift JIS FULLWIDTH LATIN SMALL LETTER I */
                              "\xEF\xBC\xAF", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER O */
                              "\xEF\xBD\x8F", /* Shift JIS FULLWIDTH LATIN SMALL LETTER O */
                              "\xEF\xBC\xAE", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER N */
                              "\xEF\xBD\x8E", /* Shift JIS FULLWIDTH LATIN SMALL LETTER N */
                              "\xEF\xBC\xAC", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER L */
                              "\xEF\xBD\x8C", /* Shift JIS FULLWIDTH LATIN SMALL LETTER L */
                              "\xEF\xBC\xB5", /* Shift JIS FULLWIDTH LATIN CAPITAL LETTER U */
                              "\xEF\xBD\x95", /* Shift JIS FULLWIDTH LATIN SMALL LETTER U */
                              "\xE2\x81\xBF", /* Shift JIS FULLWIDTH SUPERSCRIPT N */
                              "\xCA\x9F", /* L UNICODE IPA Extension */
                              "\xCA\x80", /* R UNICODE IPA Extension */
                              "\xC9\xB4"
        ),  /* N UNICODE IPA Extension */
	array(
            'l',
            'l',
            'r',
            'r',
            'n',
            'n',
            'E',
            'E',
            'e',
            'e',
            'X',
            'X',
            'x',
            'x',
            'P',
            'P',
            'p',
            'p',
            'R',
            'R',
            'r',
            'r',
            'S',
            'S',
            's',
            's',
            'I',
            'I',
            'i',
            'i',
            'O',
            'O',
            'o',
            'o',
            'N',
            'N',
            'n',
            'n',
            'L',
            'L',
            'l',
            'l',
            'U',
            'U',
            'u',
            'u',
            'n',
            'n',
            'E',
            'e',
            'X',
            'x',
            'P',
            'p',
            'R',
            'r',
            'S',
            's',
            'I',
            'i',
            'O',
            'o',
            'N',
            'n',
            'L',
            'l',
            'U',
            'u',
            'n',
            'l',
            'r',
            'n'
        )
    );
    $attvalue = str_replace($aDangerousCharsReplacementTable[0], $aDangerousCharsReplacementTable[1], $attvalue);
    
    // Escapes are useful for special characters like "{}[]()'&. In other cases they are
    // used for XSS.
    $attvalue = preg_replace("/(\\\\)([a-zA-Z]{1})/", '$2', $attvalue);
}

/**
 * This function returns the final tag out of the tag name, an array
 * of attributes, and the type of the tag.
 * This function is called by
 * sq_sanitize internally.
 *
 * @param $tagname the
 *            name of the tag.
 * @param $attary the
 *            array of attributes and their values
 * @param $tagtype The
 *            type of the tag (see in comments).
 * @return a string with the final tag representation.
 */
function sq_tagprint($tagname, $attary, $tagtype)
{
    $me = 'sq_tagprint';
    
    if ($tagtype == 2) {
        $fulltag = '</' . $tagname . '>';
    } else {
        $fulltag = '<' . $tagname;
        if (is_array($attary) && sizeof($attary)) {
            $atts = Array();
            while (list ($attname, $attvalue) = each($attary)) {
                array_push($atts, "$attname=$attvalue");
            }
            $fulltag .= ' ' . join(" ", $atts);
        }
        if ($tagtype == 3) {
            $fulltag .= ' /';
        }
        $fulltag .= '>';
    }
    return $fulltag;
}

/**
 * A small helper function to use with array_walk.
 * Modifies a by-ref
 * value and makes it lowercase.
 *
 * @param $val a
 *            value passed by-ref.
 * @return void since it modifies a by-ref value.
 */
function sq_casenormalize(&$val)
{
    $val = strtolower($val);
}

/**
 * This function skips any whitespace from the current position within
 * a string and to the next non-whitespace value.
 *
 * @param $body the
 *            string
 * @param $offset the
 *            offset within the string where we should start
 *            looking for the next non-whitespace character.
 * @return the location within the $body where the next
 *         non-whitespace char is located.
 */
function sq_skipspace($body, $offset)
{
    $me = 'sq_skipspace';
    preg_match('/^(\s*)/s', substr($body, $offset), $matches);
    if (sizeof($matches{1})) {
        $count = strlen($matches{1});
        $offset += $count;
    }
    return $offset;
}

/**
 * This function looks for the next character within a string.
 * It's
 * really just a glorified "strpos", except it catches if failures
 * nicely.
 *
 * @param $body The
 *            string to look for needle in.
 * @param $offset Start
 *            looking from this position.
 * @param $needle The
 *            character/string to look for.
 * @return location of the next occurance of the needle, or
 *         strlen($body) if needle wasn't found.
 */
function sq_findnxstr($body, $offset, $needle)
{
    $me = 'sq_findnxstr';
    $pos = strpos($body, $needle, $offset);
    if ($pos === FALSE) {
        $pos = strlen($body);
    }
    return $pos;
}

/**
 * This function takes a PCRE-style regexp and tries to match it
 * within the string.
 *
 * @param $body The
 *            string to look for needle in.
 * @param $offset Start
 *            looking from here.
 * @param $reg A
 *            PCRE-style regex to match.
 * @return Returns a false if no matches found, or an array
 *         with the following members:
 *         - integer with the location of the match within $body
 *         - string with whatever content between offset and the match
 *         - string with whatever it is we matched
 */
function sq_findnxreg($body, $offset, $reg)
{
    $me = 'sq_findnxreg';
    $matches = Array();
    $retarr = Array();
    preg_match("%^(.*?)($reg)%si", substr($body, $offset), $matches);
    if (! isset($matches{0}) || ! $matches{0}) {
        $retarr = false;
    } else {
        $retarr{0} = $offset + strlen($matches{1});
        $retarr{1} = $matches{1};
        $retarr{2} = $matches{2};
    }
    return $retarr;
}

/**
 * This function looks for the next tag.
 *
 * @param $body String
 *            where to look for the next tag.
 * @param $offset Start
 *            looking from here.
 * @return false if no more tags exist in the body, or
 *         an array with the following members:
 *         - string with the name of the tag
 *         - array with attributes and their values
 *         - integer with tag type (1, 2, or 3)
 *         - integer where the tag starts (starting "<")
 *         - integer where the tag ends (ending ">")
 *         first three members will be false, if the tag is invalid.
 */
function sq_getnxtag($body, $offset)
{
    $me = 'sq_getnxtag';
    if ($offset > strlen($body)) {
        return false;
    }
    $lt = sq_findnxstr($body, $offset, "<");
    if ($lt == strlen($body)) {
        return false;
    }
    /**
     * We are here:
     * blah blah <tag attribute="value">
     * \---------^
     */
    $pos = sq_skipspace($body, $lt + 1);
    if ($pos >= strlen($body)) {
        return Array(
            false,
            false,
            false,
            $lt,
            strlen($body)
        );
    }
    /**
     * There are 3 kinds of tags:
     * 1.
     * Opening tag, e.g.:
     * <a href="blah">
     * 2. Closing tag, e.g.:
     * </a>
     * 3. XHTML-style content-less tag, e.g.:
     * <img src="blah" />
     */
    $tagtype = false;
    switch (substr($body, $pos, 1)) {
        case '/':
            $tagtype = 2;
            $pos ++;
            break;
        case '!':
            /**
             * A comment or an SGML declaration.
             */
            if (substr($body, $pos + 1, 2) == "--") {
                $gt = strpos($body, "-->", $pos);
                if ($gt === false) {
                    $gt = strlen($body);
                } else {
                    $gt += 2;
                }
                return Array(
                    false,
                    false,
                    false,
                    $lt,
                    $gt
                );
            } else {
                $gt = sq_findnxstr($body, $pos, ">");
                return Array(
                    false,
                    false,
                    false,
                    $lt,
                    $gt
                );
            }
            break;
        default:
            /**
             * Assume tagtype 1 for now.
             * If it's type 3, we'll switch values
             * later.
             */
            $tagtype = 1;
            break;
    }
    
    $tag_start = $pos;
    $tagname = '';
    /**
     * Look for next [\W-_], which will indicate the end of the tag name.
     */
    $regary = sq_findnxreg($body, $pos, "[^\w\-_]");
    if ($regary == false) {
        return Array(
            false,
            false,
            false,
            $lt,
            strlen($body)
        );
    }
    list ($pos, $tagname, $match) = $regary;
    $tagname = strtolower($tagname);
    
    /**
     * $match can be either of these:
     * '>' indicating the end of the tag entirely.
     * '\s' indicating the end of the tag name.
     * '/' indicating that this is type-3 xhtml tag.
     *
     * Whatever else we find there indicates an invalid tag.
     */
    switch ($match) {
        case '/':
            /**
             * This is an xhtml-style tag with a closing / at the
             * end, like so: <img src="blah" />.
             * Check if it's followed
             * by the closing bracket. If not, then this tag is invalid
             */
            if (substr($body, $pos, 2) == "/>") {
                $pos ++;
                $tagtype = 3;
            } else {
                $gt = sq_findnxstr($body, $pos, ">");
                $retary = Array(
                    false,
                    false,
                    false,
                    $lt,
                    $gt
                );
                return $retary;
            }
        case '>':
            return Array(
                $tagname,
                false,
                $tagtype,
                $lt,
                $pos
            );
            break;
        default:
            /**
             * Check if it's whitespace
             */
            if (! preg_match('/\s/', $match)) {
                /**
                 * This is an invalid tag! Look for the next closing ">".
                 */
                $gt = sq_findnxstr($body, $lt, ">");
                return Array(
                    false,
                    false,
                    false,
                    $lt,
                    $gt
                );
            }
            break;
    }
    
    /**
     * At this point we're here:
     * <tagname attribute='blah'>
     * \-------^
     *
     * At this point we loop in order to find all attributes.
     */
    $attname = '';
    $atttype = false;
    $attary = Array();
    
    while ($pos <= strlen($body)) {
        $pos = sq_skipspace($body, $pos);
        if ($pos == strlen($body)) {
            /**
             * Non-closed tag.
             */
            return Array(
                false,
                false,
                false,
                $lt,
                $pos
            );
        }
        /**
         * See if we arrived at a ">" or "/>", which means that we reached
         * the end of the tag.
         */
        $matches = Array();
        if (preg_match("%^(\s*)(>|/>)%s", substr($body, $pos), $matches)) {
            /**
             * Yep.
             * So we did.
             */
            $pos += strlen($matches{1});
            if ($matches{2} == "/>") {
                $tagtype = 3;
                $pos ++;
            }
            return Array(
                $tagname,
                $attary,
                $tagtype,
                $lt,
                $pos
            );
        }
        
        /**
         * There are several types of attributes, with optional
         * [:space:] between members.
         * Type 1:
         * attrname[:space:]=[:space:]'CDATA'
         * Type 2:
         * attrname[:space:]=[:space:]"CDATA"
         * Type 3:
         * attr[:space:]=[:space:]CDATA
         * Type 4:
         * attrname
         *
         * We leave types 1 and 2 the same, type 3 we check for
         * '"' and convert to "&quot" if needed, then wrap in
         * double quotes. Type 4 we convert into:
         * attrname="yes".
         */
        $regary = sq_findnxreg($body, $pos, "[^:\w\-_]");
        if ($regary == false) {
            /**
             * Looks like body ended before the end of tag.
             */
            return Array(
                false,
                false,
                false,
                $lt,
                strlen($body)
            );
        }
        list ($pos, $attname, $match) = $regary;
        $attname = strtolower($attname);
        /**
         * We arrived at the end of attribute name.
         * Several things possible
         * here:
         * '>' means the end of the tag and this is attribute type 4
         * '/' if followed by '>' means the same thing as above
         * '\s' means a lot of things -- look what it's followed by.
         * anything else means the attribute is invalid.
         */
        switch ($match) {
            case '/':
                /**
                 * This is an xhtml-style tag with a closing / at the
                 * end, like so: <img src="blah" />.
                 * Check if it's followed
                 * by the closing bracket. If not, then this tag is invalid
                 */
                if (substr($body, $pos, 2) == "/>") {
                    $pos ++;
                    $tagtype = 3;
                } else {
                    $gt = sq_findnxstr($body, $pos, ">");
                    $retary = Array(
                        false,
                        false,
                        false,
                        $lt,
                        $gt
                    );
                    return $retary;
                }
            case '>':
                $attary{$attname} = '"yes"';
                return Array(
                    $tagname,
                    $attary,
                    $tagtype,
                    $lt,
                    $pos
                );
                break;
            default:
                /**
                 * Skip whitespace and see what we arrive at.
                 */
                $pos = sq_skipspace($body, $pos);
                $char = substr($body, $pos, 1);
                /**
                 * Two things are valid here:
                 * '=' means this is attribute type 1 2 or 3.
                 * \w means this was attribute type 4.
                 * anything else we ignore and re-loop. End of tag and
                 * invalid stuff will be caught by our checks at the beginning
                 * of the loop.
                 */
                if ($char == "=") {
                    $pos ++;
                    $pos = sq_skipspace($body, $pos);
                    /**
                     * Here are 3 possibilities:
                     * "'" attribute type 1
                     * '"' attribute type 2
                     * everything else is the content of tag type 3
                     */
                    $quot = substr($body, $pos, 1);
                    if ($quot == "'") {
                        $regary = sq_findnxreg($body, $pos + 1, "\'");
                        if ($regary == false) {
                            return Array(
                                false,
                                false,
                                false,
                                $lt,
                                strlen($body)
                            );
                        }
                        list ($pos, $attval, $match) = $regary;
                        $pos ++;
                        $attary{$attname} = "'" . $attval . "'";
                    } else 
                        if ($quot == '"') {
                            $regary = sq_findnxreg($body, $pos + 1, '\"');
                            if ($regary == false) {
                                return Array(
                                    false,
                                    false,
                                    false,
                                    $lt,
                                    strlen($body)
                                );
                            }
                            list ($pos, $attval, $match) = $regary;
                            $pos ++;
                            $attary{$attname} = '"' . $attval . '"';
                        } else {
                            /**
                             * These are hateful.
                             * Look for \s, or >.
                             */
                            $regary = sq_findnxreg($body, $pos, "[\s>]");
                            if ($regary == false) {
                                return Array(
                                    false,
                                    false,
                                    false,
                                    $lt,
                                    strlen($body)
                                );
                            }
                            list ($pos, $attval, $match) = $regary;
                            /**
                             * If it's ">" it will be caught at the top.
                             */
                            $attval = preg_replace("/\"/s", "&quot;", $attval);
                            $attary{$attname} = '"' . $attval . '"';
                        }
                } else 
                    if (preg_match("|[\w/>]|", $char)) {
                        /**
                         * That was attribute type 4.
                         */
                        $attary{$attname} = '"yes"';
                    } else {
                        /**
                         * An illegal character.
                         * Find next '>' and return.
                         */
                        $gt = sq_findnxstr($body, $pos, ">");
                        return Array(
                            false,
                            false,
                            false,
                            $lt,
                            $gt
                        );
                    }
                break;
        }
    }
    /**
     * The fact that we got here indicates that the tag end was never
     * found.
     * Return invalid tag indication so it gets stripped.
     */
    return Array(
        false,
        false,
        false,
        $lt,
        strlen($body)
    );
}

/**
 * Translates entities into literal values so they can be checked.
 *
 * @param $attvalue the
 *            by-ref value to check.
 * @param $regex the
 *            regular expression to check against.
 * @param $hex whether
 *            the entites are hexadecimal.
 * @return True or False depending on whether there were matches.
 */
function sq_deent(&$attvalue, $regex, $hex = false)
{
    $me = 'sq_deent';
    $ret_match = false;
    preg_match_all($regex, $attvalue, $matches);
    if (is_array($matches) && sizeof($matches[0]) > 0) {
        $repl = Array();
        for ($i = 0; $i < sizeof($matches[0]); $i ++) {
            $numval = $matches[1][$i];
            if ($hex) {
                $numval = hexdec($numval);
            }
            $repl{$matches[0][$i]} = chr($numval);
        }
        $attvalue = strtr($attvalue, $repl);
        return true;
    } else {
        return false;
    }
}

/**
 * This function runs various checks against the attributes.
 *
 * @param $tagname String
 *            with the name of the tag.
 * @param $attary Array
 *            with all tag attributes.
 * @param $rm_attnames See
 *            description for sq_sanitize
 * @param $bad_attvals See
 *            description for sq_sanitize
 * @param $add_attr_to_tag See
 *            description for sq_sanitize
 * @param $message message
 *            object
 * @param $id message
 *            id
 * @param $mailbox mailbox            
 * @return Array with modified attributes.
 */
function sq_fixatts($tagname, $attary, $rm_attnames, $bad_attvals, $add_attr_to_tag, $message, $id, $mailbox)
{
    $me = 'sq_fixatts';
    if (! is_array($attary) || ! is_object($attary)) {
        return $attary;
    }
    while (list ($attname, $attvalue) = each($attary)) {
        /**
         * See if this attribute should be removed.
         */
        foreach ($rm_attnames as $matchtag => $matchattrs) {
            if (preg_match($matchtag, $tagname)) {
                foreach ($matchattrs as $matchattr) {
                    if (preg_match($matchattr, $attname)) {
                        unset($attary{$attname});
                        continue;
                    }
                }
            }
        }
        
        /**
         * Workaround for IE quirks
         */
        sq_fixIE_idiocy($attvalue);
        
        /**
         * Remove any backslashes, entities, and extraneous whitespace.
         */
        $oldattvalue = $attvalue;
        sq_defang($attvalue);
        if ($attname == 'style' && $attvalue !== $oldattvalue) {
            // entities are used in the attribute value. In 99% of the cases it's there as XSS
            // i.e.<div style="{ left:exp&#x0280;essio&#x0274;( alert('XSS') ) }">
            $attvalue = "idiocy";
            $attary{$attname} = $attvalue;
        }
        sq_unspace($attvalue);
        
        /**
         * Now let's run checks on the attvalues.
         * I don't expect anyone to comprehend this. If you do,
         * get in touch with me so I can drive to where you live and
         * shake your hand personally. :)
         */
        foreach ($bad_attvals as $matchtag => $matchattrs) {
            if (preg_match($matchtag, $tagname)) {
                foreach ($matchattrs as $matchattr => $valary) {
                    if (preg_match($matchattr, $attname)) {
                        /**
                         * There are two arrays in valary.
                         * First is matches.
                         * Second one is replacements
                         */
                        list ($valmatch, $valrepl) = $valary;
                        $newvalue = preg_replace($valmatch, $valrepl, $attvalue);
                        if ($newvalue != $attvalue) {
                            $attary{$attname} = $newvalue;
                            $attvalue = $newvalue;
                        }
                    }
                }
            }
        }
        if ($attname == 'style') {
            if (preg_match('/[\0-\37\200-\377]+/', $attvalue)) {
                // 8bit and control characters in style attribute values can be used for XSS, remove them
                $attary{$attname} = '"disallowed character"';
            }
            preg_match_all("/url\s*\((.+)\)/si", $attvalue, $aMatch);
            if (count($aMatch)) {
                foreach ($aMatch[1] as $sMatch) {
                    // url value
                    $urlvalue = $sMatch;
                    sq_fix_url($attname, $urlvalue, $message, $id, $mailbox, "'");
                    $attary{$attname} = str_replace($sMatch, $urlvalue, $attvalue);
                }
            }
        } /**
         * Use white list based filtering on attributes which can contain url's
         */
        else 
            if ($attname == 'href' || $attname == 'src' || $attname == 'background') {
                sq_fix_url($attname, $attvalue, $message, $id, $mailbox);
                $attary{$attname} = $attvalue;
            }
    }
    /**
     * See if we need to append any attributes to this tag.
     */
    foreach ($add_attr_to_tag as $matchtag => $addattary) {
        if (preg_match($matchtag, $tagname)) {
            $attary = array_merge($attary, $addattary);
        }
    }
    return $attary;
}

/**
 * set the image if enable show
 *
 * @param $attvalue String
 *            with attribute value to filter
 * @param $message message
 *            object
 * @param $id message
 *            id
 * @param $mailbox mailbox            
 * @param $sQuote quoting
 *            characters around url's
 */
function sq_fix_url($attname, &$attvalue, $message, $id, $mailbox, $sQuote = '"')
{
    $attvalue = trim($attvalue);
    if ($attvalue && ($attvalue[0] == '"' || $attvalue[0] == "'")) {
        // remove the double quotes
        $sQuote = $attvalue[0];
        $attvalue = trim(substr($attvalue, 1, - 1));
    }
    
    // If there's no "view_unsafe_images" variable in the URL, turn unsafe
    // images off by default.
    $view_unsafe_images = TRUE;
    
    $secremoveimg = '../images/' . _("sec_remove_eng.png");
    
    /**
     * Replace empty src tags with the blank image.
     * src is only used
     * for frames, images, and image inputs. Doing a replace should
     * not affect them working as should be, however it will stop
     * IE from being kicked off when src for img tags are not set
     */
    if ($attvalue == '') {
        $attvalue = '"' . SM_PATH . 'images/blank.png"';
    } else {
        // first, disallow 8 bit characters and control characters
        if (preg_match('/[\0-\37\200-\377]+/', $attvalue)) {
            switch ($attname) {
                case 'href':
                    $attvalue = $sQuote . 'http://invalid-stuff-detected.example.com' . $sQuote;
                    break;
                default:
                    $attvalue = $sQuote . SM_PATH . 'images/blank.png' . $sQuote;
                    break;
            }
        } else {
            $aUrl = parse_url($attvalue);
            if (isset($aUrl['scheme'])) {
                switch (strtolower($aUrl['scheme'])) {
                    case 'mailto':
                    case 'http':
                    case 'https':
                    case 'ftp':
                        if ($attname != 'href') {
                            if ($view_unsafe_images == false) {
                                $attvalue = $sQuote . $secremoveimg . $sQuote;
                            } else {
                                if (isset($aUrl['path'])) {
                                    
                                    // No one has been able to show that image URIs
                                    // can be exploited, so for now, no restrictions
                                    // are made at all. If this proves to be a problem,
                                    // the commented-out code below can be of help.
                                    // (One consideration is that I see nothing in this
                                    // function that specifically says that we will
                                    // only ever arrive here when inspecting an image
                                    // tag, although that does seem to be the end
                                    // result - e.g., <script src="..."> where malicious
                                    // image URIs are in fact a problem are already
                                    // filtered out elsewhere.
                                    /*
                                     * ---------------------------------
                                     * // validate image extension.
                                     * $ext = strtolower(substr($aUrl['path'],strrpos($aUrl['path'],'.')));
                                     * if (!in_array($ext,array('.jpeg','.jpg','xjpeg','.gif','.bmp','.jpe','.png','.xbm'))) {
                                     * // If URI is to something other than
                                     * // a regular image file, get the contents
                                     * // and try to see if it is an image.
                                     * // Don't use Fileinfo (finfo_file()) because
                                     * // we'd need to make the admin configure the
                                     * // location of the magic.mime file (FIXME: add finfo_file() support later?)
                                     * //
                                     * $mime_type = '';
                                     * if (function_exists('mime_content_type')
                                     * && ($FILE = @fopen($attvalue, 'rb', FALSE))) {
                                     *
                                     * // fetch file
                                     * //
                                     * $file_contents = '';
                                     * while (!feof($FILE)) {
                                     * $file_contents .= fread($FILE, 8192);
                                     * }
                                     * fclose($FILE);
                                     *
                                     * // store file locally
                                     * //
                                     * global $attachment_dir, $username;
                                     * $hashed_attachment_dir = getHashedDir($username, $attachment_dir);
                                     * $localfilename = GenerateRandomString(32, '', 7);
                                     * $full_localfilename = "$hashed_attachment_dir/$localfilename";
                                     * while (file_exists($full_localfilename)) {
                                     * $localfilename = GenerateRandomString(32, '', 7);
                                     * $full_localfilename = "$hashed_attachment_dir/$localfilename";
                                     * }
                                     * $FILE = fopen("$hashed_attachment_dir/$localfilename", 'wb');
                                     * fwrite($FILE, $file_contents);
                                     * fclose($FILE);
                                     *
                                     * // get mime type and remove file
                                     * //
                                     * $mime_type = mime_content_type("$hashed_attachment_dir/$localfilename");
                                     * unlink("$hashed_attachment_dir/$localfilename");
                                     * }
                                     * // debug: echo "$attvalue FILE TYPE IS $mime_type<HR>";
                                     * if (substr(strtolower($mime_type), 0, 5) != 'image') {
                                     * $attvalue = $sQuote . SM_PATH . 'images/blank.png'. $sQuote;
                                     * }
                                     * }
                                     * ---------------------------------
                                     */
                                } else {
                                    $attvalue = $sQuote . SM_PATH . 'images/blank.png' . $sQuote;
                                }
                            }
                        } else {
                            $attvalue = $sQuote . $attvalue . $sQuote;
                        }
                        break;
                    case 'outbind':
                        /**
                         * "Hack" fix for Outlook using propriatary outbind:// protocol in img tags.
                         * One day MS might actually make it match something useful, for now, falling
                         * back to using cid2http, so we can grab the blank.png.
                         */
                        $attvalue = $sQuote . sq_cid2http($message, $id, $attvalue, $mailbox) . $sQuote;
                        break;
                    case 'cid':
                        /**
                         * Turn cid: urls into http-friendly ones.
                         */
                        $attvalue = $sQuote . sq_cid2http($message, $id, $attvalue, $mailbox) . $sQuote;
                        break;
                    default:
                        $attvalue = $sQuote . SM_PATH . 'images/blank.png' . $sQuote;
                        break;
                }
            } else {
                if (! (isset($aUrl['path']) && $aUrl['path'] == $secremoveimg)) {
                    // parse_url did not lead to satisfying result
                    $attvalue = $sQuote . SM_PATH . 'images/blank.png' . $sQuote;
                }
            }
        }
    }
}

/**
 * fix <style>
 * Enter description here .
 * ..
 * 
 * @param
 *            $body
 * @param
 *            $pos
 * @param
 *            $message
 * @param
 *            $id
 * @param
 *            $mailbox
 */
function sq_fixstyle($body, $pos, $message, $id, $mailbox)
{
    // FIXME: Is the global "view_unsafe_images" really needed here?
    global $view_unsafe_images;
    $me = 'sq_fixstyle';
    
    // workaround for </style> in between comments
    $iCurrentPos = $pos;
    $content = '';
    $sToken = '';
    $bSucces = false;
    $bEndTag = false;
    for ($i = $pos, $iCount = strlen($body); $i < $iCount; ++ $i) {
        $char = $body{$i};
        switch ($char) {
            case '<':
                $sToken = $char;
                break;
            case '/':
                if ($sToken == '<') {
                    $sToken .= $char;
                    $bEndTag = true;
                } else {
                    $content .= $char;
                }
                break;
            case '>':
                if ($bEndTag) {
                    $sToken .= $char;
                    if (preg_match('/\<\/\s*style\s*\>/i', $sToken, $aMatch)) {
                        $newpos = $i + 1;
                        $bSucces = true;
                        break 2;
                    } else {
                        $content .= $sToken;
                    }
                    $bEndTag = false;
                } else {
                    $content .= $char;
                }
                break;
            case '!':
                if ($sToken == '<') {
                    // possible comment
                    if (isset($body{$i + 2}) && substr($body, $i, 3) == '!--') {
                        $i = strpos($body, '-->', $i + 3);
                        if ($i === false) { // no end comment
                            $i = strlen($body);
                        }
                        $sToken = '';
                    }
                } else {
                    $content .= $char;
                }
                break;
            default:
                if ($bEndTag) {
                    $sToken .= $char;
                } else {
                    $content .= $char;
                }
                break;
        }
    }
    if ($bSucces == FALSE) {
        return array(
            FALSE,
            strlen($body)
        );
    }
    
    /**
     * First look for general BODY style declaration, which would be
     * like so:
     * body {background: blah-blah}
     * and change it to .
     * bodyclass so we can just assign it to a <div>
     */
    $content = preg_replace("|body(\s*\{.*?\})|si", ".bodyclass\\1", $content);
    // $secremoveimg = '../images/' . _("sec_remove_eng.png");
    
    // first check for 8bit sequences and disallowed control characters
    if (preg_match('/[\16-\37\200-\377]+/', $content)) {
        $content = '<!-- style block removed by html filter due to presence of 8bit characters -->';
        return array(
            $content,
            $newpos
        );
    }
    
    // IE Sucks hard. We have a special function for it.
    sq_fixIE_idiocy($content);
    
    // remove @import line
    $content = preg_replace("/^\s*(@import.*)$/mi", "\n<!-- @import rules forbidden -->\n", $content);
    
    /**
     * Fix url('blah') declarations.
     */
    // translate ur\l and variations into url (IE parses that)
    // TODO check if the sq_fixIE_idiocy function already handles this.
    $content = preg_replace("/(\\\\)?u(\\\\)?r(\\\\)?l(\\\\)?/i", 'url', $content);
    preg_match_all("/url\s*\((.+)\)/si", $content, $aMatch);
    if (count($aMatch)) {
        $aValue = $aReplace = array();
        foreach ($aMatch[1] as $sMatch) {
            // url value
            $urlvalue = $sMatch;
            sq_fix_url('style', $urlvalue, $message, $id, $mailbox, "'");
            $aValue[] = $sMatch;
            $aReplace[] = $urlvalue;
        }
        $content = str_replace($aValue, $aReplace, $content);
    }
    
    /**
     * Remove any backslashes, entities, and extraneous whitespace.
     */
    $contentTemp = $content;
    sq_defang($contentTemp);
    sq_unspace($contentTemp);
    
    /**
     * Fix stupid css declarations which lead to vulnerabilities
     * in IE.
     *
     * Also remove "position" attribute, as it can easily be set
     * to "fixed" or "absolute" with "left" and "top" attributes
     * of zero, taking over the whole content frame. It can also
     * be set to relative and move itself anywhere it wants to,
     * displaying content in areas it shouldn't be allowed to touch.
     */
    $match = Array(
        '/\/\*.*\*\//',
        '/expression/i',
        '/behaviou*r/i',
        '/binding/i',
        '/include-source/i',
        '/javascript/i',
        '/script/i',
        '/position/i'
    );
    $replace = Array(
        '',
        'idiocy',
        'idiocy',
        'idiocy',
        'idiocy',
        'idiocy',
        'idiocy',
        ''
    );
    $contentNew = preg_replace($match, $replace, $contentTemp);
    if ($contentNew !== $contentTemp) {
        // insecure css declarations are used. From now on we don't care
        // anymore if the css is destroyed by sq_deent, sq_unspace or sq_unbackslash
        $content = $contentNew;
    }
    return array(
        $content,
        $newpos
    );
}

/**
 * This function converts cid: url's into the ones that can be viewed in
 * the browser.
 *
 * @param $message the
 *            message object
 * @param $id the
 *            message id
 * @param $cidurl the
 *            cid: url.
 * @param $mailbox the
 *            message mailbox
 * @return a string with a http-friendly url
 */
function sq_cid2http($message, $id, $cidurl, $mailbox)
{
    /**
     * Get rid of quotes.
     */
    $quotchar = substr($cidurl, 0, 1);
    if ($quotchar == '"' || $quotchar == "'") {
        $cidurl = str_replace($quotchar, "", $cidurl);
    } else {
        $quotchar = '';
    }
    $cidurl = substr(trim($cidurl), 4);
    
    $match_str = '/\{.*?\}\//';
    $str_rep = '';
    $cidurl = preg_replace($match_str, $str_rep, $cidurl);
    
    $linkurl = find_ent_id($cidurl, $message);
    /*
     * in case of non-safe cid links $httpurl should be replaced by a sort of
     * unsafe link image
     */
    $httpurl = '';
    
    /**
     * This is part of a fix for Outlook Express 6.x generating
     * cid URLs without creating content-id headers.
     * These images are
     * not part of the multipart/related html mail. The html contains
     * <img src="cid:{some_id}/image_filename.ext"> references to
     * attached images with as goal to render them inline although
     * the attachment disposition property is not inline.
     */
    
    if (empty($linkurl)) {
        if (preg_match('/{.*}\//', $cidurl)) {
            $cidurl = preg_replace('/{.*}\//', '', $cidurl);
            if (! empty($cidurl)) {
                $linkurl = find_ent_id($cidurl, $message);
            }
        }
    }
    
    if (! empty($linkurl)) {
        $httpurl = $quotchar . SM_PATH . 'src/download.php?absolute_dl=true&amp;' . "passed_id=$id&amp;mailbox=" . urlencode($mailbox) . '&amp;ent_id=' . $linkurl . $quotchar;
    } else {
        /**
         * If we couldn't generate a proper img url, drop in a blank image
         * instead of sending back empty, otherwise it causes unusual behaviour
         */
        $httpurl = $quotchar . SM_PATH . 'images/blank.png' . $quotchar;
    }
    
    return $httpurl;
}

/**
 * This function changes the <body> tag into a <div> tag since we
 * can't really have a body-within-body.
 *
 * @param $attary an
 *            array of attributes and values of <body>
 * @param $mailbox mailbox
 *            we're currently reading (for cid2http)
 * @param $message current
 *            message (for cid2http)
 * @param $id current
 *            message id (for cid2http)
 * @return a modified array of attributes to be set for <div>
 */
function sq_body2div($attary, $mailbox, $message, $id)
{
    $me = 'sq_body2div';
    $divattary = Array(
        'class' => "'bodyclass'"
    );
    $bgcolor = '#ffffff';
    $text = '#000000';
    $styledef = '';
    if (is_array($attary) && sizeof($attary) > 0) {
        foreach ($attary as $attname => $attvalue) {
            $quotchar = substr($attvalue, 0, 1);
            $attvalue = str_replace($quotchar, "", $attvalue);
            switch ($attname) {
                case 'background':
                    $attvalue = sq_cid2http($message, $id, $attvalue, $mailbox);
                    $styledef .= "background-image: url('$attvalue'); ";
                    break;
                case 'bgcolor':
                    $styledef .= "background-color: $attvalue; ";
                    break;
                case 'text':
                    $styledef .= "color: $attvalue; ";
                    break;
            }
        }
        if (strlen($styledef) > 0) {
            $divattary{"style"} = "\"$styledef\"";
        }
    }
    return $divattary;
}

/**
 * This is the main function and the one you should actually be calling.
 * There are several variables you should be aware of an which need
 * special description.
 *
 * Since the description is quite lengthy, see it here:
 * http://linux.duke.edu/projects/mini/htmlfilter/
 *
 * @param $body the
 *            string with HTML you wish to filter
 * @param $tag_list see
 *            description above
 * @param $rm_tags_with_content see
 *            description above
 * @param $self_closing_tags see
 *            description above
 * @param $force_tag_closing see
 *            description above
 * @param $rm_attnames see
 *            description above
 * @param $bad_attvals see
 *            description above
 * @param $add_attr_to_tag see
 *            description above
 * @param $message message
 *            object
 * @param $id message
 *            id
 * @return sanitized html safe to show on your pages.
 */
function sq_sanitize($body, $tag_list, $rm_tags_with_content, $self_closing_tags, $force_tag_closing, $rm_attnames, $bad_attvals, $add_attr_to_tag, $message, $id, $mailbox)
{
    $me = 'sq_sanitize';
    $rm_tags = array_shift($tag_list);
    /**
     * Normalize rm_tags and rm_tags_with_content.
     */
    @array_walk($tag_list, 'sq_casenormalize');
    @array_walk($rm_tags_with_content, 'sq_casenormalize');
    @array_walk($self_closing_tags, 'sq_casenormalize');
    /**
     * See if tag_list is of tags to remove or tags to allow.
     * false means remove these tags
     * true means allow these tags
     */
    $curpos = 0;
    $open_tags = Array();
    $trusted = "\n<!-- begin sanitized html -->\n";
    $skip_content = false;
    /**
     * Take care of netscape's stupid javascript entities like
     * &{alert('boo')};
     */
    $body = preg_replace("/&(\{.*?\};)/si", "&amp;\\1", $body);
    
    while (($curtag = sq_getnxtag($body, $curpos)) != FALSE) {
        list ($tagname, $attary, $tagtype, $lt, $gt) = $curtag;
        $free_content = substr($body, $curpos, $lt - $curpos);
        /**
         * Take care of <style>
         */
        if ($tagname == "style" && $tagtype == 1) {
            list ($free_content, $curpos) = sq_fixstyle($body, $gt + 1, $message, $id, $mailbox);
            if ($free_content != FALSE) {
                if (! is_array($attary)) {
                    $attary = array(
                        $attary
                    );
                }
                $attary = sq_fixatts($tagname, $attary, $rm_attnames, $bad_attvals, $add_attr_to_tag, $message, $id, $mailbox);
                
                $trusted .= sq_tagprint($tagname, $attary, $tagtype);
                $trusted .= $free_content;
                $trusted .= sq_tagprint($tagname, false, 2);
            }
            continue;
        }
        if ($skip_content == false) {
            $trusted .= $free_content;
        }
        if ($tagname != false) {
            if ($tagtype == 2) {
                if ($skip_content == $tagname) {
                    /**
                     * Got to the end of tag we needed to remove.
                     */
                    $tagname = false;
                    $skip_content = false;
                } else {
                    if ($skip_content == false) {
                        if ($tagname == "body") {
                            $tagname = "div";
                        }
                        if (isset($open_tags{$tagname}) && $open_tags{$tagname} > 0) {
                            $open_tags{$tagname} --;
                        } else {
                            $tagname = false;
                        }
                    }
                }
            } else {
                /**
                 * $rm_tags_with_content
                 */
                if ($skip_content == false) {
                    /**
                     * See if this is a self-closing type and change
                     * tagtype appropriately.
                     */
                    if ($tagtype == 1 && in_array($tagname, $self_closing_tags)) {
                        $tagtype = 3;
                    }
                    /**
                     * See if we should skip this tag and any content
                     * inside it.
                     */
                    if ($tagtype == 1 && in_array($tagname, $rm_tags_with_content)) {
                        $skip_content = $tagname;
                    } else {
                        if (($rm_tags == false && in_array($tagname, $tag_list)) || ($rm_tags == true && ! in_array($tagname, $tag_list))) {
                            $tagname = false;
                        } else {
                            /**
                             * Convert body into div.
                             */
                            if ($tagname == "body") {
                                $tagname = "div";
                                $attary = sq_body2div($attary, $mailbox, $message, $id);
                            }
                            if ($tagtype == 1) {
                                if (isset($open_tags{$tagname})) {
                                    $open_tags{$tagname} ++;
                                } else {
                                    $open_tags{$tagname} = 1;
                                }
                            }
                            /**
                             * This is where we run other checks.
                             */
                            if (is_array($attary) && sizeof($attary) > 0) {
                                $attary = sq_fixatts($tagname, $attary, $rm_attnames, $bad_attvals, $add_attr_to_tag, $message, $id, $mailbox);
                            }
                        }
                    }
                }
            }
            if ($tagname != false && $skip_content == false) {
                $trusted .= sq_tagprint($tagname, $attary, $tagtype);
            }
        }
        $curpos = $gt + 1;
    }
    $trusted .= substr($body, $curpos, strlen($body) - $curpos);
    if ($force_tag_closing == true) {
        foreach ($open_tags as $tagname => $opentimes) {
            while ($opentimes > 0) {
                $trusted .= '</' . $tagname . '>';
                $opentimes --;
            }
        }
        $trusted .= "\n";
    }
    $trusted .= "<!-- end sanitized html -->\n";
    return $trusted;
}

/**
 *
 * @param $body the
 *            body of the message
 * @param $id the
 *            id of the message
 * @param boolean $take_mailto_links
 *            When TRUE, converts mailto: links
 *            into internal SM compose links
 *            (optional; default = TRUE)
 * @return a string with html safe to display in the browser.
 */
function magicHTML($body, $id, $message, $mailbox = 'INBOX', $take_mailto_links = true)
{
    global $has_unsafe_images;
    $view_unsafe_images = true;
    $force_tag_closing = true;
    $take_mailto_links = false;
    /**
     * Don't display attached images in HTML mode.
     */
    // $attachment_common_show_images = false;
    $tag_list = Array(
        false,
        "object",
        "meta",
        "html",
        "head",
        "base",
        "link",
        "frame",
        "iframe",
        "plaintext",
        "marquee"
    );
    $rm_tags_with_content = Array(
        "script",
        "applet",
        "embed",
        "title",
        "frameset",
        "xmp",
        "xml"
    );
    $self_closing_tags = Array(
        "img",
        "br",
        "hr",
        "input",
        "outbind"
    );
    $rm_attnames = Array(
        "/.*/" => Array(
            "/target/i",
            "/^on.*/i",
            "/^dynsrc/i",
            "/^data.*/i",
            "/^lowsrc.*/i"
        )
    );
    
    $secremoveimg = "../images/" . 'sec_remove_eng.png';
    $bad_attvals = Array(
        "/.*/" => Array(
            "/^src|background/i" => Array(
                Array(
                    "/^([\'\"])\s*\S+script\s*:.*([\'\"])/si",
                    "/^([\'\"])\s*mocha\s*:*.*([\'\"])/si",
                    "/^([\'\"])\s*about\s*:.*([\'\"])/si"
                ),
                Array(
                    "\\1$secremoveimg\\2",
                    "\\1$secremoveimg\\2",
                    "\\1$secremoveimg\\2"
                )
            ),
            "/^href|action/i" => Array(
                Array(
                    "/^([\'\"])\s*\S+script\s*:.*([\'\"])/si",
                    "/^([\'\"])\s*mocha\s*:*.*([\'\"])/si",
                    "/^([\'\"])\s*about\s*:.*([\'\"])/si"
                ),
                Array(
                    "\\1#\\1",
                    "\\1#\\1",
                    "\\1#\\1"
                )
            ),
            "/^style/i" => Array(
                Array(
                    "/\/\*.*\*\//",
                    "/expression/i",
                    "/binding/i",
                    "/behaviou*r/i",
                    "/include-source/i",
                    
                    // position:relative can also be exploited
                    // to put content outside of email body area
                    // and position:fixed is similarly exploitable
                    // as position:absolute, so we'll remove it
                    // altogether....
                    //
                    // Does this screw up legitimate HTML messages?
                    // If so, the only fix I see is to allow position
                    // attributes (any values? I think we still have
                    // to block static and fixed) only if $use_iframe
                    // is enabled (1.5.0+)
                    //
                    // was: "/position\s*:\s*absolute/i",
                    //
                    "/position\s*:/i",
                    "/(\\\\)?u(\\\\)?r(\\\\)?l(\\\\)?/i",
                    "/url\s*\(\s*([\'\"])\s*\S+script\s*:.*([\'\"])\s*\)/si",
                    "/url\s*\(\s*([\'\"])\s*mocha\s*:.*([\'\"])\s*\)/si",
                    "/url\s*\(\s*([\'\"])\s*about\s*:.*([\'\"])\s*\)/si",
                    "/(.*)\s*:\s*url\s*\(\s*([\'\"]*)\s*\S+script\s*:.*([\'\"]*)\s*\)/si"
                ),
                Array(
                    "",
                    "idiocy",
                    "idiocy",
                    "idiocy",
                    "idiocy",
                    "idiocy",
                    "url",
                    "url(\\1#\\1)",
                    "url(\\1#\\1)",
                    "url(\\1#\\1)",
                    "\\1:url(\\2#\\3)"
                )
            )
        )
    );
    if (! $view_unsafe_images) {
        array_push($bad_attvals{'/.*/'}{'/^src|background/i'}[0], '/^([\'\"])\s*https*:.*([\'\"])/si');
        array_push($bad_attvals{'/.*/'}{'/^src|background/i'}[1], "\\1$secremoveimg\\1");
        array_push($bad_attvals{'/.*/'}{'/^style/i'}[0], '/url\([\'\"]?https?:[^\)]*[\'\"]?\)/si');
        array_push($bad_attvals{'/.*/'}{'/^style/i'}[1], "url(\\1$secremoveimg\\1)");
    }
    
    $add_attr_to_tag = Array(
        "/^a$/i" => Array(
            'target' => '"_blank"',
            'title' => '"' . 'This external link will open in a new window' . '"'
        )
    );
    $trusted = sq_sanitize($body, $tag_list, $rm_tags_with_content, $self_closing_tags, $force_tag_closing, $rm_attnames, $bad_attvals, $add_attr_to_tag, $message, $id, $mailbox);
    if (strpos($trusted, $secremoveimg)) {
        $has_unsafe_images = true;
    }
    if ($take_mailto_links) {
        // parseUrl($trusted); // this even parses URLs inside of tags... too aggressive
        global $MailTo_PReg_Match;
        $MailTo_PReg_Match = '/mailto:' . substr($MailTo_PReg_Match, 1);
        if ((preg_match_all($MailTo_PReg_Match, $trusted, $regs)) && ($regs[0][0] != '')) {
            foreach ($regs[0] as $i => $mailto_before) {
                $mailto_params = $regs[10][$i];
                // get rid of any tailing quote since we have to add send_to to the end
                //
                if (substr($mailto_before, strlen($mailto_before) - 1) == '"')
                    $mailto_before = substr($mailto_before, 0, strlen($mailto_before) - 1);
                if (substr($mailto_params, strlen($mailto_params) - 1) == '"')
                    $mailto_params = substr($mailto_params, 0, strlen($mailto_params) - 1);
                
                if ($regs[1][$i]) { // if there is an email addr before '?', we need to merge it with the params
                    $to = 'to=' . $regs[1][$i];
                    if (strpos($mailto_params, 'to=') > - 1) // already a 'to='
                        $mailto_params = str_replace('to=', $to . '%2C%20', $mailto_params);
                    else {
                        if ($mailto_params) // already some params, append to them
                            $mailto_params .= '&amp;' . $to;
                        else
                            $mailto_params .= '?' . $to;
                    }
                }
                $url_str = preg_replace(array(
                    '/to=/i',
                    '/(?<!b)cc=/i',
                    '/bcc=/i'
                ), array(
                    'send_to=',
                    'send_to_cc=',
                    'send_to_bcc='
                ), $mailto_params);
                
                // we'll already have target=_blank, no need to allow comp_in_new
                // here (which would be a lot more work anyway)
                //
                global $compose_new_win;
                $temp_comp_in_new = $compose_new_win;
                $compose_new_win = 0;
                $comp_uri = makeComposeLink('src/compose.php' . $url_str, $mailto_before, 'right');
                $compose_new_win = $temp_comp_in_new;
                
                $comp_uri = substr($comp_uri, 9);
                $comp_uri = substr($comp_uri, 0, strpos($comp_uri, '"', 1));
                $trusted = str_replace($mailto_before, $comp_uri, $trusted);
            }
        }
    }
    return $trusted;
}

/**
 * function SendDownloadHeaders - send file to the browser
 *
 * Original Source: SM core src/download.php
 * moved here to make it available to other code, and separate
 * front end from back end functionality.
 *
 * @param string $type0
 *            first half of mime type
 * @param string $type1
 *            second half of mime type
 * @param string $filename
 *            filename to tell the browser for downloaded file
 * @param boolean $force
 *            whether to force the download dialog to pop
 * @param
 *            optional integer $filesize send the Content-Header and length to the browser
 * @return void
 */
function SendDownloadHeaders($type0, $type1, $filename, $force, $filesize = 0)
{
    global $languages, $squirrelmail_language;
    $isIE = $isIE6plus = false;
    
    $HTTP_USER_AGENT = $_SERVER['HTTP_USER_AGENT'];
    if (strstr($HTTP_USER_AGENT, 'compatible; MSIE ') !== false && strstr($HTTP_USER_AGENT, 'Opera') === false) {
        $isIE = true;
    }
    
    if (preg_match('/compatible; MSIE ([0-9]+)/', $HTTP_USER_AGENT, $match) && ((int) $match[1]) >= 6 && strstr($HTTP_USER_AGENT, 'Opera') === false) {
        $isIE6plus = true;
    }
    
    if (isset($languages[$squirrelmail_language]['XTRA_CODE']) && function_exists($languages[$squirrelmail_language]['XTRA_CODE'])) {
        $filename = $languages[$squirrelmail_language]['XTRA_CODE']('downloadfilename', $filename, $HTTP_USER_AGENT);
    } else {
        $filename = preg_replace('/[\\\\\/:*?"<>|;]/', '_', str_replace('&#32;', ' ', $filename));
    }
    
    // A Pox on Microsoft and it's Internet Explorer!
    //
    // IE has lots of bugs with file downloads.
    // It also has problems with SSL. Both of these cause problems
    // for us in this function.
    //
    // See this article on Cache Control headers and SSL
    // http://support.microsoft.com/default.aspx?scid=kb;en-us;323308
    //
    // The best thing you can do for IE is to upgrade to the latest
    // version
    // set all the Cache Control Headers for IE
    if ($isIE) {
        // $filename=rawurlencode($filename);
        header("Pragma: public");
        header("Cache-Control: no-store, max-age=0, no-cache, must-revalidate"); // HTTP/1.1
        header("Cache-Control: post-check=0, pre-check=0", false);
        header("Cache-Control: private");
        
        // set the inline header for IE, we'll add the attachment header later if we need it
        header("Content-Disposition: inline; filename=$filename");
    }
    
    if (! $force) {
        // Try to show in browser window
        header("Content-Disposition: inline; filename=\"$filename\"");
        header("Content-Type: $type0/$type1; name=\"$filename\"");
    } else {
        // Try to pop up the "save as" box
        
        // IE makes this hard. It pops up 2 save boxes, or none.
        // http://support.microsoft.com/support/kb/articles/Q238/5/88.ASP
        // http://support.microsoft.com/default.aspx?scid=kb;EN-US;260519
        // But, according to Microsoft, it is "RFC compliant but doesn't
        // take into account some deviations that allowed within the
        // specification." Doesn't that mean RFC non-compliant?
        // http://support.microsoft.com/support/kb/articles/Q258/4/52.ASP
        
        // all browsers need the application/octet-stream header for this
        header("Content-Type: application/octet-stream; name=\"$filename\"");
        
        // http://support.microsoft.com/support/kb/articles/Q182/3/15.asp
        // Do not have quotes around filename, but that applied to
        // "attachment"... does it apply to inline too?
        header("Content-Disposition: attachment; filename=\"$filename\"");
        
        if ($isIE && ! $isIE6plus) {
            // This combination seems to work mostly. IE 5.5 SP 1 has
            // known issues (see the Microsoft Knowledge Base)
            
            // This works for most types, but doesn't work with Word files
            header("Content-Type: application/download; name=\"$filename\"");
            // This is to prevent IE for MIME sniffing and auto open a file in IE
            header("Content-Type: application/force-download; name=\"$filename\"");
            // These are spares, just in case. :-)
            // header("Content-Type: $type0/$type1; name=\"$filename\"");
            // header("Content-Type: application/x-msdownload; name=\"$filename\"");
            // header("Content-Type: application/octet-stream; name=\"$filename\"");
        } else 
            if ($isIE) {
                // This is to prevent IE for MIME sniffing and auto open a file in IE
                header("Content-Type: application/force-download; name=\"$filename\"");
            } else {
                // another application/octet-stream forces download for Netscape
                header("Content-Type: application/octet-stream; name=\"$filename\"");
            }
    }
    // send the content-length header if the calling function provides it
    if ($filesize > 0) {
        header("Content-Length: $filesize");
    }
}  // end fn SendDownloadHeaders
